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117 lines
4.2 KiB
Markdown
117 lines
4.2 KiB
Markdown
PicoHTTPParser
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=============
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Copyright (c) 2009-2014 [Kazuho Oku](https://github.com/kazuho), [Tokuhiro Matsuno](https://github.com/tokuhirom), [Daisuke Murase](https://github.com/typester), [Shigeo Mitsunari](https://github.com/herumi)
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PicoHTTPParser is a tiny, primitive, fast HTTP request/response parser.
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Unlike most parsers, it is stateless and does not allocate memory by itself.
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All it does is accept pointer to buffer and the output structure, and setups the pointers in the latter to point at the necessary portions of the buffer.
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The code is widely deployed within Perl applications through popular modules that use it, including [Plack](https://metacpan.org/pod/Plack), [Starman](https://metacpan.org/pod/Starman), [Starlet](https://metacpan.org/pod/Starlet), [Furl](https://metacpan.org/pod/Furl). It is also the HTTP/1 parser of [H2O](https://github.com/h2o/h2o).
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Check out [test.c] to find out how to use the parser.
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The software is dual-licensed under the Perl License or the MIT License.
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Usage
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-----
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The library exposes four functions: `phr_parse_request`, `phr_parse_response`, `phr_parse_headers`, `phr_decode_chunked`.
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### phr_parse_request
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The example below reads an HTTP request from socket `sock` using `read(2)`, parses it using `phr_parse_request`, and prints the details.
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```c
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char buf[4096], *method, *path;
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int pret, minor_version;
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struct phr_header headers[100];
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size_t buflen = 0, prevbuflen = 0, method_len, path_len, num_headers;
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ssize_t rret;
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while (1) {
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/* read the request */
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while ((rret = read(sock, buf + buflen, sizeof(buf) - buflen)) == -1 && errno == EINTR)
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;
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if (rret <= 0)
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return IOError;
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prevbuflen = buflen;
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buflen += rret;
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/* parse the request */
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num_headers = sizeof(headers) / sizeof(headers[0]);
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pret = phr_parse_request(buf, buflen, &method, &method_len, &path, &path_len,
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&minor_version, headers, &num_headers, prevbuflen);
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if (pret > 0)
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break; /* successfully parsed the request */
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else if (pret == -1)
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return ParseError;
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/* request is incomplete, continue the loop */
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assert(pret == -2);
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if (buflen == sizeof(buf))
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return RequestIsTooLongError;
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}
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printf("request is %d bytes long\n", pret);
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printf("method is %.*s\n", (int)method_len, method);
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printf("path is %.*s\n", (int)path_len, path);
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printf("HTTP version is 1.%d\n", minor_version);
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printf("headers:\n");
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for (i = 0; i != num_headers; ++i) {
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printf("%.*s: %.*s\n", (int)headers[i].name_len, headers[i].name,
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(int)headers[i].value_len, headers[i].value);
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}
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```
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### phr_parse_response, phr_parse_headers
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`phr_parse_response` and `phr_parse_headers` provide similar interfaces as `phr_parse_request`. `phr_parse_response` parses an HTTP response, and `phr_parse_headers` parses the headers only.
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### phr_decode_chunked
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The example below decodes incoming data in chunked-encoding. The data is decoded in-place.
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```c
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struct phr_chunked_decoder decoder = {}; /* zero-clear */
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char *buf = malloc(4096);
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size_t size = 0, capacity = 4096, rsize;
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ssize_t rret, pret;
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/* set consume_trailer to 1 to discard the trailing header, or the application
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* should call phr_parse_headers to parse the trailing header */
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decoder.consume_trailer = 1;
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do {
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/* expand the buffer if necessary */
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if (size == capacity) {
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capacity *= 2;
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buf = realloc(buf, capacity);
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assert(buf != NULL);
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}
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/* read */
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while ((rret = read(sock, buf + size, capacity - size)) == -1 && errno == EINTR)
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;
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if (rret <= 0)
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return IOError;
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/* decode */
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rsize = rret;
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pret = phr_decode_chunked(&decoder, buf + size, &rsize);
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if (pret == -1)
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return ParseError;
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size += rsize;
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} while (pret == -2);
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/* successfully decoded the chunked data */
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assert(pret >= 0);
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printf("decoded data is at %p (%zu bytes)\n", buf, size);
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```
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Benchmark
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---------
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The benchmark code is from [fukamachi/fast-http@6b91103](https://github.com/fukamachi/fast-http/tree/6b9110347c7a3407310c08979aefd65078518478).
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The internals of picohttpparser has been described to some extent in [my blog entry]( http://blog.kazuhooku.com/2014/11/the-internals-h2o-or-how-to-write-fast.html).
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